Projectile.



T. A. EDISON.

PROJECTILE.

APPLICATION FILED JAN-24 ISIS.

' Patnted Mar. 11,1919..

grnrns rn'ranr or'rica.

THGMAS A. EDISON, 0F LLEWELLYN PARK, WEST ORANGE, NEW JERSEY.

PROJECTILE.

meanest.

citizen of the United States, and a resident of Y Llewellyn Park, WestOrange, Essex county, New Jersey, have invented certain new and usefulImprovements in Projectiles, of which the following is a description.

My invention relates in general to projectiles, and more especially toprojectiles 10 designed for use in guns of large caliber. In practicallyall types of guns now made which discharge only a single projectile at atime, the bores of the guns are rifled or provided with longitudinallyextending twisted grooves, whereby a rapid rotary movement will beimparted to a projectile about its longitudinal axis when dischargedfrom, such a gun. The rotary movement thus imparted to the projectileproduces a gyroscopic' action whichovercomes the tendency of theprojectile to turn end over end, or hurtle in its trajectory, andconsequently insures the striking of the projectile head on and alsogreatly increases the degree of accuracy obtainable. In the continueduse of such guns, however, the rifled bores thereof erode, thisresulting in a loss of-accuracy and sooner or later, the hurtling of theprojectile in its flight. This erosion of the bores in guns of verylarge caliber, for example, in a 16 inch gun, is very rapid, due to thegreat pressure, heat, and friction-produced in the discharge thereof,and consequently it is possible to discharge such a gun only a fewtimes, with any degree of accuracy and safety, before it is necessary torepair or replace the same, and this, to-

. gether with the great cost of repairing or replacing such guns,renders the use thereof impracticable. j

The principal object of my invention is the provision of a projectile ofsuch construction that when. the same is discharged from a smooth boreor unrifled gun, the tendency thereof to hurtle or turn end over end inflight is overcome, and the accuracy obtainable is at least as great asthat obtainable'with projectiles discharged from the rifled gunsheretofore used. As the erosion of the bore of such a gun is veryslight, and a high degree of accuracy may therefore be obtainedtherewith during a great number of rounds, my invention renders the useof guns of very large caliber much more practicable than heretofore,

Specification of Letters Patent.

Patented Mar. 11, 1919.

Application filed January 24, 1916. Serial No, 73,868.

Other objects and features of my invention will be hereinafter morefully described and claimed. a

For a clearer understanding of my invention, attention is directed tothe accompany-4 ing drawing, forming part of this specification, and inwhich:

Figure 1 is a View in side elevation, partly in section, of a projectilemade in accordance with my invention; and

Fig. 2 is a sectional view taken-on line 22 of Fig. 1. 7

Referring to the drawing, the projectile comprises a cylindrical bodyportion 1 and a reduced portion at the forward end thereof, preferablyin the form of,a pointed head or nose 2. The forward or head end portionof the projectile is preferably heavier than the rear end portionthereof, this preferably being accomplished by providing the projectileat the rear end portion thereof with a cylindrical longitudinallyextending recess or cavity 3. Accordingly, the projectile has a tendencyto travel head on in its trajectory. If the projectile is to be used asa shell, the recess 3 may be filled with any form of a sleeve shrunk onor otherwise applied and secured to the projectile. The for ward endportion of the projectile is also preferably provided with a cylindricalcollar 6, preferably of about one-third the entire length of theprojectile, and preferably having an extension 7 projecting a slightdistance beyond the body portion 1 and over the reduced portion or nose2, thereby providing an annular space 8 between the extension 7 and thenose 2. The collar 6 may be formed integrally with the body portion 1,but is preferabl in the form of a cylindrical sleeve .whic is shrunk onor otherwise applied and secured to the body portion 1 of theprojectile. The collars 5 and 6 are of the same diameter and are detheportions 11 preferably gradually decreases rearwardly of the projectile,as

clearly shown in the drawing, until such portions merge in the surfaceof the body portion 1. The, collar 6 covers the grooves 9 for a greaterpart of their length, thereby forming inclosed channels or passagewayswhichcommunicate at their forward ends with the annular space 8.

When the projectile above described is discharged from a gun, air isentrapped in the space 8 and forced through the bent or twisted grooves9, thereby causing the projectile to rotate about its longitudinal axiswith great rapidity. The resulting gyroscopic action will prevent theprojectile from turning end over end or hurtling in its flight.Accordingly, a gun with a smooth bore may be employed for discharging aprojectile of this type. As the portions of the projectile engaging thebore of thegun are also smooth, the erosion of the bore takes place veryslowly and the life of the gun and the number of rounds during which ahigh degree of accuracy is obtainable are comparatively great.

large caliber, for example, 16 inch and 18 inch guns. The provision ofthe projectile with an extension or lip, such as shown at 7, I regard asa very important feature of my invention, as this extension or lipserves to entrap air within the annular space 8 during the flight of theprojectile, and it is believed that the air thus entrapped, in the caseof a projectile traveling at a great velocity, will prevent hurtling ofthe projectile even though the grooves 9 be omitted or are formedparallel to the axis of the projectile for their entire length. Thegrooves 9, when formed as shown in the-drawing, serve a purpose slmilarto that of the rifling grooves in the bores of guns as usually made, andmay, indeed, be designated as rifling grooves or riflings.

While I have shown anddescribed the preferred embodiment of myinvention, it is to be understood that the same is subject to'variouschanges and modifications without any departure from the spirit of theinvention and the scope of the appended claims,

My invention therefore. renders it practicable to employ guns of very-Having now described my invention, what,

I claim and desire to secure by Letters Patent of the United States isas follows 1. A projectile comprising a body portion and having one endportion heavier than the other end portion thereof, the heavierendportion of the projectile being provided with a plurality oflongitudinally extending open ended grooves formed on the exterior ofsaid body portion, said grooves being covered for a part at least oftheir length and being spaced circumferentially of the projectile,substantially as described.

2. A cylindricalprojectile provided with a plurality of longitudinallyextending openended grooves, a portion of each of said grooves beingsubstantially parallel to the axis of the projectile and another portionthereof extending from said first portion atan angle thereto, the latterportions decreasing in depth until they merge in the surface of the bodyportion of the projectile.

3. A cylindrical projectile having a head end portion which is heavierthan its rear end portion, the projectile being provided with aplurality of longitudinally extending open-ended grooves,'a portion ofeach of said grooves being substantially parallel to the axis of theprojectile and another portion thereof extending from said first portionat an angle thereto, the portions of the a grooves which aresubstantially parallel to the axis of the projectile being nearer thehead end of'th'e projectile, and the other portions of the groovesextending rearwardly therefrom and decreasing in depth until they mergein the surface of the body portion of the projectile, substantially asdescribed.

4. A projectile comprising a cylindrical body portion, a reduced portionat one end of said body portion, and a collar on said body'portion, saidcollar extending beyond said body portion over said reduced portion,thereby. providing an annular space between said collar and reducedportion, the projectile being provided beneath said collar withopen-ended longitudinally extend- -ing grooves which communicate withsaid space, substantially as described.

5. A projectile comprlsin body portion and a reduce portion, said bodyportion having an extension projecting over said reduced portlon andprov1d-' ing an annular space between such extension and reducedportion, the projectile being provided with a plurality oflongitudinally extending open-ended grooves communicata cylindrical ingwith said space, substantially as described.

6. A cylindrical projectile, the head end portion only of which isprovided with a collar and with a plurality of longitudinally extendingopen ended grooves beneath said collar, said grooves being spaced,circumferentially-of the projectile, substantially as described.

7 A cylindrical projectile provided with a plurality of longitudinallyextending open ended grooves, a portion of each of said grooves beingsubstantially parallel to the axis of the projectile and another portionthereof extending from said first portion at ans-angle thereto, a partof said angular portions of said grooves being uncovered, andz-ascollareouering the remainder of said grooves," substantially as described.

8. A, cylindrical projectile having a head end" portion which is heavierthan its rears: end portion, the projectile being provided with asplurality of longitudinally extending: open -ended'tgnooves, a portion.of each" of said grooves being substantially parallel to the axis ofthe pro ectile and another portion thereof extending from said firstportion at an angle thereto, the portions of the grooves Which aresubstantially parallel to the axis of the projectile being nearer thehead end of the projectile than the angular portions of the grooves, apart of said angular portions being uncovered, and a collar covering theremainder of said grooves, substantially as described.

This specification signed and witnessed this 11th day of January, 1916.

THOS; A: EDISON.

